Confirmation of water in the form of ice on Mercury and the Moon, and the discovery of structurally bond OH on the Moon, Vesta and possibly other asteroids, suggest that “water” is more widely distributed in the inner solar system than previously thought. It is possible that some common set of sources and mechanisms is responsible for forming and preserving ”water” on these airless bodies. However, the origin of their water is still unclear. Possible sources include cometary and chondritic input, interior degassing, or solar wind. The relative contribution of these sources may vary among different airless bodies.

The Moon is the only of these places where we have direct geological sampling and diverse surface soil samples. Study of lunar samples provides important constraints on possible formation and preservation mechanisms of water on airless bodies. Here we report results from our continuing efforts to determine the distribution and abundances of water in lunar soils of different maturity and compositions. These results will be combined with recent experimental work on solar-wind absorption and desorption, as well as literature data on bulk soils, to understand the preservation of water into the micrometeorite-impact generated melt.